1. Field of the Invention
The present invention relates to carburetors as used with motor vehicles. More particularly, the present invention the relates to carburetors that cause the return of fuel from the carburetor to the fuel tank. Additionally, the present invention relates to a return line from the carburetor that has a nozzle positioned therein.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
Carburetors are used in motor vehicles for passing the fuel into the engine for combustion. In the carburetor, the fuel is mixed with air for delivery into the cylinders. Conventional carburetors utilize inlets that serve to deliver the fuel for mixture with the air. In particular, the fuel is delivered through a needle-and-seat valve so as to accumulate within a fuel bowl within the carburetor. It can then be passed as a fuel/air mixture from the fuel bowl into the engine. Conventionally, carburetors have outlet openings formed thereon. Typically, these outlet openings are closed.
In normal use, as fuel leaves the fuel tank, the fuel proceeds through the fuel line to either an electric fuel pump or a mechanical fuel pump and to a fuel regulator. The fuel then flows through a fuel filter so as to eventually make its way into the fuel inlets on one side of the carburetor. The fuel awaits propulsion into the jets by continuing up through the needle-and-seat and into the bowls of the carburetor. Ultimately, the fuel is transmitted to venturis where it is mixed with ambient air and sent down the intake manifold such that combustion can occur within the engine.
With conventional carburetion systems, as the vehicle is driven on the freeway or sitting in traffic, the fuel remains standing in the fuel lines and absorbs heat from various sources before actually entering into the carburetor fuel bowls. These sources of heat can include heat from the radiator, engine heat (from the intake manifold, the exhaust manifold or the headers, and the engine block) and ambient air temperature (most critical during the summer months). As a result of these external heat sources, the fuel becomes superheated and begins to boil in the lines before reaching the bowls on the carburetor. Once this superheated fuel enters the fuel bowl, it percolates so as to create an aerated fuel. Upon acceleration, this aerated fuel enters into the jets located in the metering block of the carburetor and effectively leans out the carburetor. This ultimately creates a stalling condition, commonly referred to as a vapor lock. Thus, there is a need for a fuel return line that causes fuel to pass back to the fuel tank so that the fuel does not vaporize before reaching the carburetor.
In the past, various patents have issued relating to fuel systems that incorporate a return line to the fuel tank. For example, U.S. Pat. No. 4,173,958, issued on Nov. 13, 1979 to Kato et al., teaches a carburetor in a fuel system in a vehicle. This fuel system includes a fuel tank, a fuel pump for delivering fuel from the fuel tank to the carburetor under pressure, and a return line which returns fuel from the carburetor to the fuel tank when an excess amount of fuel is delivered to the carburetor by the fuel pump. The carburetor further includes a check valve in the return line for preventing the flow of fuel in the return line in a direction from the fuel tank to the carburetor. As such, the fuel flowing backwardly through the return line is prevented from leaking into the carburetor when the vehicle is turned upside down in an accident.
U.S. Pat. No. 4,175,527, issued on Nov. 27, 1979 to Sanada et al., shows a fuel supply system for engines. This fuel supply system has a fuel tank divided into first and second chambers, a fuel supply passage having a fuel pump for supplying fuel from the fuel tank to a carburetor of the engine, and a fuel return passage for returning the excess fuel supplied to the carburetor to the second chamber of the fuel tank. An upper region of the second chamber is bled, while the first chamber is supplied with new fuel. The fuel supply passage includes a change-over valve which usually connects the fuel supply passage to the first chamber.
U.S. Pat. No. 4,195,608, issued on Apr. 1, 1980 to Sanada et al., teaches a fuel supply system for engines having a carburetor. The carburetor has a float chamber and a vapor bleed passage connected to the float chamber. A portion of a fuel supply passage supplies fuel from a fuel tank to the carburetor and traverses through the float chamber so that the fuel flowing through the fuel supply passage absorbs heat from the fuel contained in the float chamber. The fuel entering into the float chamber releases volatile light components as vapor towards the vapor bleed passage while the liquid fuel contained in the float chamber becomes a more stable liquid due to the release of volatile components and the cooling effected by heat exchange with the fuel flowing through the fuel supply passage.
U.S. Pat. No. 4,582,039, issued on Apr. 15, 1986 to H. Nishida, shows a fuel supply system having a suction-type fuel supply so as to supply fuel through a fuel pump to a carburetor which is located at a level higher than the fuel level of the main fuel tank. A reserve fuel tank is provided on the line connecting the main fuel tank with the fuel pump. The reserve tank is at a level higher than the carburetor and the fuel pump. The fuel outlet of the reserve tank is located at a level lower than the fuel inlet.
U.S. Pat. No. 4,811,718, issued on Mar. 14, 1989 to S. Sonoda, shows a fuel supply system having a suction pump provided in a fuel supply passage, a ventilation passage for allowing interior space of a fuel tank to be communicated with the atmosphere, a normally-closed ventilation valve disposed in the ventilation passage, and a normally-closed release valve disposed in the fuel return passage. The normally-closed release valve is adapted for opening the fuel return passage at the time of start-up of the engine.
U.S. Pat. No. 4,835,866, issued on Jun. 6, 1989 to A. Nagashima, provides a construction for mounting a carburetor on a machine. This construction has a driving internal combustion engine, such as a portable chain saw. The carburetor is directly fixed to a fuel tank annexed to the engine and the mixture delivery side of the carburetor is connected through a resilient heat-insulating pipe to the suction port of the internal combustion engine.
U.S. Pat. No. 6,655,335, issued on Dec. 2, 2003 to Imafuku et al., discloses a small engine for outdoor power equipment. Fuel is pumped to the engine's combustion chamber by a reciprocating piston. Undesired engine racing is avoided by restricting airflow to the carburetor. A choke mechanism is provided with a pair of end portions. One of the pair of end portions closes air to the carburetor for starting and the other provides a spaced barrier for inhibiting blow-back.
U.S. Pat. No. 6,840,262, issued on Jan. 11, 2005 to T. Kojima, teaches a fuel blocking valve device having a housing attached to a fuel tank of a vehicle. A communication path extends between an inside and an outside of the fuel tank. A float valve serves to close the communication path when fuel flows into the housing. A two-way valve is disposed above the float vale for opening and closing according to an inner pressure of the tank.
U.S. Pat. No. 6,901,892, issued on Jun. 7, 2005 to Mavinahally, provides a two-stroke internal combustion engine which has at least one gaseous communication passage between a crankcase chamber and a combustion chamber of the engine. A first rotary shut-off valve on a periphery of a rotatable circular disk is operatively disposed between the passage and the crankcase chamber and rotatably connected to a crankshaft of the engine.
It is an object of the present invention to provide a fuel system for a vehicle that effectively cools the fuel passing through the fuel line.
It is another object of the present invention to provide a fuel system for a vehicle that allows the vehicle to run more efficiently.
It is another object of the present invention to provide a fuel system for a vehicle that serves to eliminate vapor locks.
It is an object of the present invention to provide a fuel system for a vehicle that improves fuel mileage.
It is still another object of the present invention to provide a fuel system for a vehicle that serves to reduce emissions.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.